1. Field of the Invention
The present invention relates generally to burial containers and methods for forming same and is particularly concerned with burial container having a seamless single piece double wall base and lid forming hollow chambers therein, the interior side of each double wall having a coarse aggregate fused thereto to bond with a flowable structural material such as concrete or foam introduced into the formed chambers for additional structural strength and/or weight.
2. Description of the Prior Art
Concrete burial vaults are porous and thus, under soil load pressure, will eventually permit the flow of moisture into the vault interior. Attempts have been made to line such vaults with plastic or fiberglass shells, however the continued pressure of soil load will eventually cause moisture to move through pores of the concrete and separate the interior shell from the concrete to which it was originally adhered.
A number of approaches have been taken to cover or shroud concrete burial vaults with plastic in order to provide a better barrier to the flow of matter into the vault interior. These approaches for the most part are directed to a technique for adhering the liner to the concrete interface. See for example U.S. Pat. No. 3,439,461 (Chandler) which describes the application of a wet and tacky adhesive onto the surfaces of a plastic liner placed on a mold for filing with concrete so that the adhesive and the concrete will cure together and be bonded at the interface. While this is an improvement in previous techniques, there is still a tendency for the liner to separate from the concrete and permit the entry of moisture.
U.S. Pat. No. 3,839,768 (McQuestion) seeks to overcome the manufacturing steps required to use adhesive as the adhering means at the plastic to concrete interface by attaching fiberglass loops to the surfaces of a resinous liner so that when the mold is filled with concrete, the loops will be embedded in the concrete. This has been successful to a degree, however the manufacturing process is involved and costly.
U.S. Pat. No. 4,060,581 (Darby) is directed to overcome the problem arising when some of the wet and tacky adhesive pre-applied to the surfaces of a plastic liner is scrubbed away when the concrete is poured into the mold. It calls for adhering aggregate to surfaces of the plastic liner so that when the mold is filled with concrete and the concrete cured, the pre-applied aggregate provides the adhering means at the plastic to concrete interface.
While these approaches have resulted in improvements in vault construction, there is still a need for a more efficient and less costly manufacturing operation and a more secure bonding between the container surface and the concrete interface. It is to this need that the present invention is directed.